Abstract: A environment-friendly lead-free cutting silicon-brass was prepared by replace lead with silicon and modification treatment, and the effects of modification treatment on morphology, hardness of γ phase and the cutting performance of the silicon-brass were studied. The results show that modification treatment not only changed γ-phase′s morphology and made it distribute diffusely in β phase in a point-like form, but also could effectively reduce the microhardness of γ phase. The gap between γ phase and β phase could play a good role for chip breaking during cutting.